The disks to be described below are those having music information recorded thereon, whereas such disks may be those having English conversation or other programs recorded thereon.
With common disk playback devices, a break occurs in the sound reproduced from disks during a change from one disk played back to another disk. This gives discomfort to the user who is desirous of listening to the reproduced sound without any interruption. In view of such experience, playback devices have been proposed which permit a change of disk without a break in the reproduced sound (see JP-A No. 69263/1997).
The proposed device is of the so-called autochanger type, which has a stacker 8 for accommodating a plurality of disks D as arranged one above another as shown in FIG. 9. The disk D is delivered from the stacker 8 by a change hand 81 of a disk changer mechanism 80. The disk D is placed on a turntable 73, and a reproduction signal is retrieved from the disk by a pickup 2 which is slidable radially of the disk. With an error signal taken out by an RF amplifier circuit 20, the reproduction signal is stored in a memory 5 by a system controller 82. Since the signal is written to the memory 5 at a rate which is always higher than the reading rate, a predetermined quantity of data is stored in the memory 5 at all times.
For a change of disk, the system controller 82 operates the disk changer mechanism 80, which places the disk on the turntable 73 into the stacker 8 and automatically takes out another disk from the stacker 8. During the changing procedure, the data remaining in the memory 5 is reproduced with no break occurring in the reproduced sound.
Portable disk playback devices have been proposed in recent years. With reference to FIG. 10 showing such a device, a base frame 70 for placing a disk thereon has a closure 7 pivoted to one side portion thereof and positionable over the disk. The disk on the playback device needs to be replaced by another one by the user himself. However, the user, while listening to the reproduced sound, is unable to recognize when to change the disk because he has no means to detect a time immediately before the completion of playback of the disk.
Such a portable disk playback device has also been proposed which is adapted to temporarily store the sound reproduced from the disk in a memory 5 and output the sound a predetermined period of time thereafter (see JP-B No. 85980/1993). The device has a vibration proof function and is adapted to correct skipping of sound. As shown in FIG. 8, the device has memory means 55 for storing the sound reproduced from the disk in the order of addresses, and sensor means 56 for detecting discontinuity of time code of the reproduced sound, i.e., inaccurate reproduction. Upon the sensor means 56 detecting a discontinuity in the time code, the pickup 2 is moved back to a position on the disk before the occurrence of the discontinuity, with writing to the memory means 55 suspended during the movement of the pickup 2. The writing to the memory means 55 is resumed after the pickup 2 has been moved. The location of the skip is not stored in the memory means 55, permitting a speaker 91 to output the reproduced sound without any break.